This new version, which Trend Micro detects as TSPY_ZBOT.SMQH, spread around late September through spam that claimed to be from the Australian Taxation Office (ATO). The spammed messages contained a malicious link that when clicked directed users to a malicious website that served the BlackHole Exploit Kit. The exploit kit, in turn, downloads a variant of the new ZeuS version.

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As we can see, unlike ZeuS 2.3.2.0, which uses Advanced Encryption Standard (AES), the decryption algorithm did not change much compared with the modified ZeuS 2, which uses RC4.

As I mentioned earlier, like LICAT and ZeuS 2.3.2.0, this new variant also seems to be crafted by a private professional gang, probably the same ones who created LICAT or who may be affiliated with them at the very least. In fact, the configuration file for TSPY_ZBOT.SMQH has the same format as that of the configuration file of LICAT.